Piston and piston-ring construction



April 24, 1926 1,666,966

R. G. HILL PISTON AND PISTON RING CONSTRUCTION Filed June 5. 1927ATTQRNEY Patented Apr. 24, 19.28.- j

,UNITED STATES PATENT OFFICE.

ROSCOE GOULD HILL, 0F RIVER FALLS, WISCONSIN, ASSIGNQB, 0F CNE-.HALF TOFREDERIC X. K NOBEL, 0l' RIVER FALLS, WISCONSIN.

PITCN ANI)v PIBTON-BING CONSTRUCTION.

Application ined :ma 3, 19a?. serial no. 196,311.

the combinations, constructions, and. arrange-` ments herein describedand claimed.

An object of my invention is to provide a novel form of pistonconstruction of the type in which iston `rings are carried 1n grooves inthe piston and are held by means of spring tension against the walls ofthe cylinder, the piston rings in the present 1n stance being providedwith thin, flexible edges which are held closely to the wall of thecylinder by the expanding gas.

A further lobject is to provide a plston ring construction in which thescoring of the cylinder or of the ring is prevente While at the sametime the rings afford a tight seal for preventing the passage of gases.

A further object is to provide a piston rmg construction in which thethin, flexible edges are maintained, even thoughl the contactlng'surface of the rings should be worn.

A further object is to provide a construction in which excessivepressure on the cylinder wall, which otherwise might cause sticking orscoring, is obviated.

Other objects and advantages will appear in the followingspecification,` and the'novel features of the invention will beparticularly pointed out in the al pended claims.

My invention is 'i lustrated in lthe accompanying drawingsLfprming partof this application, in which"'-"' Figure 1 is a longitudinal sectionalview through a portion of a piston and cylinder showing the pistonrings,

Figure 2 is a face view of one of the piston rings,

I` igure 3 is a section along the line 3--3 of Figure 2,

and

Figure 5 is a sectional view similar to Figure 1, showing a modifiedform of the device. In carryingout my invention, I provide a piston suchas that shown in F1 re 1 having a head 1 and side walls 2. p the resentinstance, the head is shown'as havmg a bevelled portion 3 adjacent tothe cylinder Wall 4.

The piston has an enlargement at the junction of the head with the Wall2, as shown at 5. This enlar ement has an annular groove 6, V-shape incross section, which lWalls of t-he cylinder.

Figure 4 is a face view of a spring ring,

roove, as it will be observed, intersects the velled portion 3 of thehead near the outer edge thereof; i. e., adjacent to the inner wall ofthe cylinder 4.

The portion 5 is also provided with au auxiliary circumferential groove7 adjacent to the Wall of the cylinder 4, and this groove communicatesbymeans of passages such as that shown at 8 with the interiorl of t-hepiston.

lower piston rings 9. These rings are precisely alike, although they are1n opposed ositions. v

as a cylinder-contacting surface 9*, a surface 9b angularly disposedtheretoand in slidable contact with Vthe walls of the V- shaped groove,a surface 9 in slidable contact with the spring ring 10, and a surface9d angularly disposed with respect to the surfaces 9c and 9*".

From the foregoing description of the various partsof the device, theoperation thereof may be readily understood. The rings are assembledwith their cylinder-contacting surfaces disposed at o posite directions.The spring ringlO ten s to contract, and in doing so it forces the rings9 outwardly into close engagement with the in ner When the pistonbecomes hot, the ring 10 tends to expand, thus allowing the rings 9 toslide inwardl 4so as to revent these rings from scoring t ecylin erwalls and also preventing excessive wear on the rings themselves. Itwill be noted that in the construction shown in Figure 1, the edge ofthe upper ringv projects beyond the bevelled portion of the piston head.This portion of the rin is thin and"4 fiexible and the pressure of t egas tends to hold it closely to the cylinder. I regard this an importantfeature of the invention because the edge is thus kept against thecylinder wall, whereas in the conventional type of piston-ring theinertia of the ring prevents 1t expandin to the enlarged middle sectionof a worn cy inder.

As'the piston rings are worn, the spring ringlO will move them outwardlyso that at all times they are in intimate contact with the inner wallsof the cylinder and the thin, flexible edges -are of course maintainedalways at the same angle. The excessive oil which is scraped oi by thepiston ring co1- Disposed in the groove `6 are upper and It will benoted that each ring lects inthe groove 7 and is lead by the passage 8into the interior 'of the piston and thence to-the crank case.

In addition to the force exerted by the spring ring 10, there is atendency, dueto thefrictional contact with the walls of the cylinder,forv the rings to be wedged outwardly. This 'further tends to keep thepiston rings in close cont-act with the walls of the cylinder. j

In Figure 5, I have shown a modified form of the device in which thecylinder head 1K is flat. .ln this form of -the device, tl1e rings i)are held by the spring ring l0 against the wall of the cylinder 4 in thesame mannerias described in connection with Figure 1. In this instance,however, the 'upper ring does not project beyond t-he head of thecylinder.

The device of the type described above provides a piston andpIston ringconstruction which may be readily assembled, which operatesautomatically to prevent scoring when the piston is hot, whichautomatically adjusts itself when worn, and in which the relation of theannular positions of the rings is at all times maintained the same.

I claim:

'1. The combination with a piston having an annular groove il-shaped inlcross section, of a-pair of piston rings, each having a surfacearranged to bear on a wall of the groove, and a contractile spring ringarranged to bear simultaneously on said piston rings and tending toforce them outwardly.

2. The-'combination with a piston having a circumferential V-shapedgroove, of a pair of piston rings, each of said piston rings having asurface arranged to engage a cylinder wall, a surface arranged to engagea wall of the V-shaped groove, and a cam surface, and a contractilespring ring disposed between said pistons rings and arranged to engagethe cam surfaces of said rings for forcing them outwardly.

3. The combination of a piston having a circumferential groove ofV-shaped cross 4c. The combination of a piston having a' circumferentialgroove of V-shaped crossscct-ion, a pair of piston rings disposed insaid groove, each of said pist-on rings having a surface arranged toengage the wall of a cylinder, a surface in engagement with a wall ofthe V-sha ed groove, and acam surface angularly disposed with respect tothe cam surface ofthe opposing piston ring, and a contractile springring disposed between the cam surfaces of the opposed piston rings forforcing said rings outwardly, one of said rings having a portion.thereof extending beyond the piston head and being subject to thepressure of the motive fluid acting on thev piston head. y 5. Thecombination of a piston having a circumferential groove V-shaped incross seetion, an auxiliary circumferential groove adjacent one edge ofsaid V-shaped groove and a passageway for affording communicationbetween said last-named groove and the interior of thepiston,.a pair ofpiston rings disposed in said V-shaped groove, each of said piston ringshaving a surface arranged to engage the wall of a cylinder, a surface inslidable engagement with a wall of said V-shaped groove and a camsurface, the cam surfaces of the piston rings being angularly disposedwith respect to one another, and a spring ring disposed in the grooveand arranged to bear on the cam surfaces of said pistonrings-and-tending to force said piston rings outwardly.

RosooE GoULD HILL.

